1. Field of the Invention
This invention relates to a distributed telephone conference control device which enables the use of ordinary telephone lines for two-party or multiparty conferencing.
2. Description of the Prior Art
The telephone equipment itself can, if employed in the normal way, be used simply to facilitate a conversation between two parties using a telephone line. However, if three or more parties wish to use the telephone to converse with each other at the same time, then a special configuration is required. In other words, real time control must be maintained in respect of multiple telephone lines while at the same time ensuring that all said lines are connected with each other on equal terms.
In order to provide the private sector with the sort of device which would enable conferencing between three or more parties, it would be possible to think in terms of, for example, a central control unit from which would radiate a number of telephones lines connected in order. The central control unit would exercise centralized control over the telephone lines concerned whenever a number of people wished to hold a telephone conference.
A central control unit would, in fact, be indispensable to the sort of technique outlined above while the scope of line control would be limited by the processing capacity of said control unit. Assuming, however, that the number of telephone lines connected into the system is likely at some future point to be increased, it is clearly going to be necessary to install a high speed processing device and this in turn introduces the problem of high initial costs. Furthermore, since the central control unit will be controlling all the lines connected into the system at the same time, this will fairly naturally place a heavy load on the system as a whole and there is a strong possibility that this may prove to be a source of future faults. Moreover, even if a central control unit with substantial capacity is installed from the outset, repeated increases in the numbers of lines connected into the system will eventually bring the central control unit to the limit of its capacity and it will then be necessary to replace it with an even more powerful unit. This brings us back to a critical problem which is that it is not possible to forecast with any degree of accuracy the future subscriber load.
It would equally be possible to digitalize voice signal lines for control by computer and to connect a number of such computers into a LAN (LOCAL AREA NETWORK). The problem here, however, would be the rapid transfer of data between units and the system would not, in fact, be realistic from the point of view of real time processing.